The VM does not like PG_private set on PG_swapcache pages. As suggestedby Trond in http://lkml.org/lkml/2006/8/25/348, this patch disablesNFS data cache revalidation on swap files. as it does not makesense to have other clients change the file while it is being used asswap. This avoids setting PG_private on swap pages, since there oughtto be no further races with invalidate_inode_pages2() to deal with.

Since we cannot set PG_private we cannot use page->private whichis already used by PG_swapcache pages to store the nfs_page. Thusaugment the new nfs_page_find_request logic.